1. Field of the Invention
The present invention relates to optical amplifiers and amplifier systems that are used to amplify light signals passing through an optical fiber network.
2. Description of the Prior Art
Optical fiber networks are used in a wide variety of applications to establish data communications between at least two remote locations. In these optical fiber networks, light signals experience losses as the signals travel through the optical fibers from one point to another. The degree of loss in the optical fiber network is due to many factors such as the length of the optical fibers, the quality of the optical fibers, splice joint reflections and the like. As a result, an initial light signal must often be amplified to compensate for losses as it travels from one point in the optical fiber network to another.
In many applications, the degree of loss between points in an optical fiber network are known. Accordingly, a fixed optical amplifier can be placed in the optical fiber network to compensate for that known loss. However, in many other applications, the optical paths in the optical fiber network are dynamically switched. As a result, a light signal traveling from one point in the optical fiber network to another may take one of several different possible optical pathways. The strength of the initial signal is the same regardless of the optical pathway traveled. However, the losses associated with each of the optical pathways is different. As a result, no one fixed amplifier or series of fixed amplifiers is ideal for all the possible optical paths where such paths are dynamically chosen.
In the prior art, amplification systems for dynamically switched optical fiber networks have been designed by averaging the needed amplification from one point in the optical fiber network to another. By averaging the required amplification, the light signal sometimes is under-amplified and other times over-amplified, depending upon the optical path followed. To compensate for the under or over-amplified signals, the optical receivers used in the optical fiber network have an exceptionally broad (frequency) operational range. In this manner, the optical receivers can receive and decipher either over amplified signals or under amplified signals. Such prior art broad band optical receivers, however, are expensive, thereby adding greatly to the cost of the overall optical fiber network.
A need therefore exists in the prior art for an optical amplifier and amplifier system that is dynamically adjustable to the exact needs of a given light signal.